[The Alchemist]

It is good that you start a big project. I think you will benefit a lot from it. It doesn't have to be better than the existing CMS, it doesn't have to be completed in the end either. But the way you go will give you boost in your skills, provided you don't give up so easily. But I am optimistic that you don't or you wouldn't have started such a project.

Just a tip, but a versioning control system can really save your ass. I wouldn't start a big project without it.
I recommend either Github or Sourceforge (unless you don't want to make it open source). Github.com uses Git, Sourceforge.net uses SVN as versioning control system. SVN is probably a bit easier for a beginner in this matter, but Git gives you more possibilities.
If you want a private repository for free, look at Bitbucket.org which uses Git too.

Thanks a lot for your kind advice...
I guess I'll be using Github.

It is always good to start on something like this in order to boost your skills. Also you can increase your toolset for future projects.

Like I already told you in the pm make sure that you have a good battleplan so you know exactly in which direction you're heading. Also make sure the base of your cms is solid/flexible so you won't need to restart coding the core because you find it inefficient after a while, which can really discourage you and, even worse, could lead to bad coding.

Features?
You probably want to have an update and plugin system in your cms, but imo it's best to start keeping it simple. I've made the mistake in the past putting way too much hay on my fork and in the end I never finished those projects.

I wish you the best of luck and do keep us updated on your progress. Do you have a name for the project already?

Thanks man...
I've not yet thought of a name for this. Maybe you could suggest me one...

@Deque and @zomgwtfbbq thanks a lot for the encouragement and advise. I'll not let you guys down.